Knob set privacy latch



Nov. 13, .1951 F. E. BEST KNOB SET PRIVACY LATCH Filed Jan. 51, 1948 INVENTOR Patented Nov. 13, 1951 UNITED STATES PATENT OFFICE KNOB SET PRIVACY LATCH Frank Ellison Best, Indianapolis, Ind.

Application January 31, 1948, Serial No. 5,599

1 Claim. 1

My invention pertains to tubular locks and latches and is particularly directed to privacy latches for use in conjunction with knob sets, especially on interior doors, such as residential bath or toilet doors.

My invention consists of a spring walled spindle lock carried. by a manually operated locking plate adapted for assembly beneath the knob set escutcheon on the interior side of said doors and adapted to lock the spindle against ordinary rotation, but to yield to forced. rotation, thus ordinarily granting privacy, but affording quick emergency entrance from the outside.

I illustrate my invention by the accompanying drawing, in which Figure 1 shows a fragment of a door and knob set, and particularly locking plate ill in longitudinal section as taken in line l-l Figure 2.

Figure 2 shows a front View of locking latch 10 and a cross-section of spindle l 2.

Figure 3 shows an alternate form II of the said locking latch.

Figure 1 shows a fragment of a door I3, with escutcheon l4 secured thereto by screws l5, trapping locking plate I in place therebetween.

Knob shank l6 and spindle l2, mating in escutcheon rose 11, complete this view.

Figure 2, shows the locking plate having the usual spring clip l9 adapted to function with the lower screw 15 to guide and hold the said locking plate in an up or a down position. It also has the usual slot 2|] adapted to cooperate with the upper screw l to align said locking plate relative to the related elements.

It is also provided with the thumb piece 2|.

The novel element of this invention consists of spring walled spindle lock 22 comprisinga stifi spring secured in place in locking plate In and adapted to normally lock the spindle I2 against rotation, when the locking plate I0 is in its up or locking position, but adapted to provide ample space for free rotation when in its unlatched or down position.

Many users of this type of lock desire means of emergency entrance and variou devices have been placed on the market to aiford such a convenience.

To meet this demand and simplify the mechanism, I have made this invention which is much simpler than former methods used, the predecessor device being set forth in Patent No. 1,760,394.

With this device installed, emergency entrance may be provided by strongly and very forcefully rotating the outside knob, under the impulse of which prongs 23 will spread apart and permit the spindle to turn, thus retracting the main belt of the tubular lock.

To any turning pressure on the outside knob of a lesser degree than said very forceful rotation, the spindle remains stationary between the vice like prongs 23 that thus indicate the room is occupied and ordinarily affords privacy.

In its lower or unlocked position, the spindle takes the dotted position 29. A dotted circle 30 shows the rotative clearance of the spindle 12 in its unlocked position.

Figure 3 shows an alternate locking plate stamped out in a single piece.

It also dispenses with spring clip 19, a slot 24 cooperating with lower screw I5 to guide and permit up and down motion of said locking plate II.

An indented spindle 25 having indents 26 is used here. The spring prongs 21 having projections 28 serve the function of locking the locking plate I I in its upper or locked position, while gravity holds it in its down or unlocked position.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent of the United States is:

In a privacy latch set, the combination of elements comprising a knob, a spindle, a rose, a spindle locking plate, a spindle opening in said locking plate, a spindle clearance portion of said opening and a spindle locking portion of said opening, a spring walled spindle lock bounding said spindle opening and a thumb piece connected to said locking plate, said locking plate being slideably housed relative to said spindle beneath said rose, and being manually positionable selectively with each of said portions of said opening contiguous with said spindle, said spring walled spindle lock normally locking said spindle against rotation when the spindle locking portion of said opening is contiguous therewith but forceably releasable when abnormal rotary torque is applied to said spindle.

FRANK ELLISON BEST.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 152,774 Steele July 7, 1874 991,018 Powers May 2, 1911 1,225,950 Fuller May 15, 1917 1,760,394 Best et a1. May 27, 1930 

